The present invention relates to latching or locking mechanisms used in motor vehicle doors.
An inspection of the prior art door latch or lock mechanisms shows a common theme. In general door lock mechanisms include manually operable interior and exterior handles, a lock button, a lock and an associated lock bar or pin, as well as a variety of mechanical linkages, cables and springs. Since the present invention is primarily related to mechanisms on the interior side of the door, the exterior door handle and its connecting linkages will not be discussed; additionally, the interface between the exterior door handle and other components of a latch/lock system are well known.
Each of the above components of the door lock mechanism, with the exception of the lock bar or pin, is typically carried by or fitted within a vehicle door. The interior door handle is used to disengage the lock from a lock bar or pin. The lock button is movable and can be manually moved, at least between a locked and an unlocked position. With the lock button in its locked position, the door handle as well as the lock is often prevented from being displaced from the lock bar or pin.
In some installations the interior handle and the lock button are physically separated and have no or only a minimal physical interaction. In other installations the interior handle and lock button are closely situated and are interconnected. One of the performance issues with this latter type of handle/lock installation is the lock button can be inadvertently moved into its locked position by the operation of the interior handle. This inadvertent locking often occurs after the interior handle has been (manually) moved or rotated to its full, active position and then quickly released. Such a quick release might occur if the handle slips out of an occupant's hand while he or she is opening the door while exiting the vehicle, that is, after the handle has been rotated to its full, active position.
An inspection of this last type of door lock mechanism shows the interior door handle and the lock button are indeed physically connected. In some installations this interconnection comprises a pin extending from the lock button, which is received within a cam slot on the interior handle. Movement of the interior handle from its rest position, through a mid-position to its active position also causes the lock button to move from its unlocked position to an over-rotated or an extended position. Subsequently, as the interior lock handle moves back to its rest position (under spring action) the cam slot creates a force on the cam pin in a direction to cause the lock button to rotate back to its unlocked position. However, if the interior handle is caused to rotate at a relatively high velocity as it returns to its rest position, the physical interconnection to the lock button via the cam slot transfers momentum to the lock button, which can cause the lock button to unduly accelerate as it moves or is moved from the extended position to its unlocked position. Consequently, the momentum transferred to the button (from the handle) in combination with spring forces acting on the lock button occasionally causes the lock button to over-rotate and inadvertently come to rest in its locked position.
Other designs of door lock mechanisms replace the above-mentioned cam and cam pin as a means of providing a degree of interconnectivity between the handle and the lock button with a plurality of the extensions, bosses or projections formed on the interior handle and/or the lock button. An inadvertent lock can still occur. When the handle is moved to its active position, one of the projections on the handle moves the lock button from its unlocked position to its extended or over-rotated position. This action is essentially the same as resulted due to the pin and cam slot interaction. A second of these projections contacts or interferes with a portion of the lock button on the return stroke of the interior handle, the effect of which is to transfer momentum to the lock button and urge the lock button toward its locked position.
As can be seen from the above, if the lock button is accelerated through its unlocked position toward its locked condition, inadvertent locking may occur. It is also believed this condition might occur even without the urging, contact or momentum transfer initiated by the interior door handle and might occur if sufficiently high spring bias forces are applied to the lock button directly or indirectly.
Some prior art solutions show the use of expensive viscous damping mechanisms to slow the motion of the door handle, which in turn controls the degree of momentum transfer to the lock button.
It is an object of the present invention to provide a simple and efficient solution to the above problem.
It is a further object of the present invention to provide a blocking mechanism to selectively block or prevent the lock button from inadvertently moving to a locked position after the door handle has been released independent of the speed of the interior door handle.
Accordingly the invention comprises: a door lock mechanism for a vehicle door comprising: a door handle manually movable from a rest position to an activated position; a first bias spring biasing the door handle to automatically return to the rest position; a lock button movable from an unlocked position to a locked position, wherein when the lock button is in the locked position an associated door lock is locked thereby preventing the door from being opened, and when the lock button is in an unlocked position the door lock is capable of being opened by the door handle when moved to the activated position, whereby a quick release of the door handle from its activated position initiates movement of the lock button from the unlocked position to the locked position; the door lock mechanism of the present invention further includes a programmed lever assembly comprising: lever means for blocking the lock button from moving to its locked position.
Many other objects and purposes of the invention will be clear from the following detailed description of the drawings.